Apparatus for preheating and handling asphalt, heavy oil, and like viscous material



, 1943' c. F. GERLINGER AND LIKE VISCOUS MATERIAL Filed June 25, 194-1 5 Sheets-Sheet l @Fun e 15 A rain/Er APPARATUS FOR PREHEATING AND HANDLING ASPHALT, HEAVY OIL, AND LIKE VISCOUS MATERIAL Filed June 25, 1941 5 Sheets-Sheet 2 June 1943 c. F. GERLINGER 2,32L90 IN V EN TOR.

rne/MK J1me 1943- F. GERLINGER 2,321,908

APPARATUS FOR PREHEATING AND HANDLING ASPHALT, HEAVY OIL, AND LIKE VISGOUS MATERIAL Filed June 25, 1941 SSheets-Sheet 3 INV/ENTOR.

A7" TOENL'Y Patent ed June 15, 1943 APPARATUS FOR PREHEATING AND HAN- DLING ASPHALT, HEAVY OIL, AND LIKE VISCOUS MATERIAL Carl F. Gerlinger, Dallas, Orez.

Application June 25, 1941, Serial No. 399,660

8 Claims.

The present invention relates to apparatus for heating and transferring asphalt, heavy oils and other like viscous materials from one container to another, and more particularly it relates to a mobile unit that can be moved from one point to another, as for example, to any railroad siding adjacent a tank car where the asphalt, heavy oil or other viscous material can be conveniently heated and transferred to a tank truck for application to a highway surface.

It is an object of my invention toprovide a practical and efficient heating and recirculating apparatus by means of which the temperature of asphalt, heavy oil and like viscous material can be raised to-thus decrease its viscosity and facilitate its application to a highway surface.

Another object of the invention is to provide a heating apparatus for raising the temperature of asphalt, heavy oil and like viscous material in which the asphalt, oil and like viscous materials are circulated through a rotary flue-type retort at varying rates of flow to the end that a scorching or carbonizing thereof is avoided.

Another object of the invention is to provide a mobile unit in which all of the apparatus, including a rotary retort and pumping equipment, is associated in such a manner that the rate of flow of the fluid and the rate of heat exchange may be conveniently controlled, and in which a single prime mover operates to drive the rotary retort and also the pumping equipment.

In heating asphalt, heavy oil and like viscous material, it is a consideration to avoid a cracking, scorching or carbonizing of the asphalt,

- heavy oil or other viscous material as its temperature is being raised. Such a cracking and scorching or carbonizing of the asphalt, heavy oil or other viscous material has the tendency to change its characteristics, and where carbonizing occurs, the carbon accumulates in the heat transfer apparatus and thus, due to its insulating character, greatly reduces the eificiency of this apparatus. At the same time, after its formation, the carbonized particles often break away and are carried along with the heated oil where it causes further damage and annoyance by plugging up the spreading jets of the distributing tank truck and results in an uneven spread of the asphalt, oil or other viscous material upon the road surface to which it is being applied. It is, therefore, a further object of the present invention to provide an apparatus in which a cracking and scorching or carbonizing of the asphalt, heavy oil or other viscous material is avoided by recirculating it through a flue-type retort in which the cool oil enters at a protected central point and recirculates outwardly until discharged from the hottest part of the retort as the retort is continuously rotated in a heating chamber. g

Other objects and advantages of the invention will be in part evident to those skilled in the art and in part pointed out hereinafter in connection with the accompanying drawings, wherein there is shown by way of illustration and not of limitation a preferred. embodiment of the invention.

In the drawings;

Figure 1 is a left-hand side view offa mobile unit constructed in accordance with the invention,

Figure 2 is a plan view of the apparatus illustrated in Figure l of the drawings,

Figure 3 is a side elevation looking at the right-hand side of the unit,

Figure 4 is a front view in elevation of the unit as illustrated in Figure 1,

Figure 5 is a diagrammatic view showing the power plant driving connections and the circulating conduits used when theapparatus is in operation, I

Figure 6 is a fragmentary partially sectionalized view showing details of a preferred form' of retort for use in apparatus of the character contemplated by the invention, and

Figures 7 and 8 are sectional views taken respectively along lines VII-VII and VIII-VIII of Figure 6 of the drawings looking in direction of the arrows.

As illustrated in the drawings, the present invention, in its preferred form, comprises a supporting frame I! upon which there is mounted a brick lined combustion chamber or firebox II that is adapted to be heated by a suitable means, as will hereinafter appear. Mounted within the combustion chamber ii there is a rotatable coil or tube-type retort I! through which asphalt, oil or other viscous material is adapted to be circulated as the retort is rotated. Associated with one end of the retort i2 and connecting with a pump ii, there is a suitable pipe or conduit ll through which a flow of the asphalt, oil or other viscous material is pumped to the retort H from a source of supply, which may be a railway tank car or a storage tank, the pump being in turn connected to the interior of the railway tank car or such storage tank by means of an additional pipe connection or conduit, as will hereinafter appear. At the other end of the retort l2 there is a discharge pipe or cond-uit ii that extends upwardly and terminates in an elevated position at a three-way valve l6 which is controlled by a hand lever H to directthe heated asphalt, oil or other viscous material from the retort 12 through either one of two branch conduits l8 and IS. The conduit i8 is preferably used to direct the heated asphalt, oil or other viscous material to a tank truck or other transporting vehicle tank for application to a highway surface, and the conduit 19 is adapted to connect with a conduit that will direct the heated asphalt, oil or other viscous material flowing from the retort 12 back to the railway tank car or storage tank for recirculation through the retort l2 until its temperature has been raised to the desired degree. As shown in Figures 1 and 2 of the drawings, the pump i3 is located at the left-hand side of the combustion chamber H and rearwardly in alignment with an internal combustion engine 20. The pump 13 is also here shown as connected to the engine 20 through a conventional automobile drive which includes a clutch that is controlled by a lever 2| and a speed changing transmission gear that is controlled by a gear shift lever 22. In addition to driving the pump l3, the internal combustion engine 20 also operates as a prime mover to drive the-rotary retort l2. As will be pointed out in more detail hereinafter, the rotary retort I2 is constructed about a central conduit 23 with which the pipe connections I4 and I connect and which also forms an axis about which the retort 12 rotates. To this end the central conduit 23 of the,retort I2 is provided with outwardly spaced trunnion wheels 24 and 25 which respectively ride upon spaced roller supports 26 and 21 arranged externally of and at the rear and forward ends of the combustion chamber ll. At these points the connections between the ends of the retort and the conduits l4 and 15 are completed through stufling boxes 28 and 29 that permit relative movement between these conduits and the retort l2 when the latter is rotated by the internal combustion engine 20. Adjacent the trunnion wheel 25, the central conduit 23 of the retort l2 also carries a sprocket over which a drive chain 30 passes. This drive chain 30 is in turn driven by a smaller sprocket of an enclosed reduction gearing 3| that is connected through a second sprocket chain 32 to a driving shaft 33 which, as will hereinafter appear, is connected in driven relation with the internal combustion engine 20.

As is more clearly illustrated in Figures 2 and 4 of the drawings, the internalcombustion engine or prime mover 20 is located at the forward end and to one side of a suitable air compressor 34 which is mounted centrally upon the frame In. The compressor 34 is adapted to be driven by the engine 20 and when in operation, it will supply compressed air for oil burners 35 and 36 which, as shown in Figure 3 of the drawings, extend into the right-hand side of the combustion chamber H. Rearwardly of the compressor 34, the frame I0 is also shown as carrying a suitable air storage tank 31 in which air is stored under pressure when the apparatus is in operation. This tank 31 has a safety relief valve 38. Above the air storage tank 31 there is a tank 39 in which fuel for the internal combustion engine 20 is carried. At the other side of the air compressor 34 and the tanks 31 and 39, the frame In also carries an additional storage tank 40 in which fuel oil for the burners 35 and 36 is carried. As is more clearly shown in Figure 3 of the drawings, the burners 35 and 36 are connected to the fuel oil supply tank 40 through a pipe line 4|, and to the compressed air storage tank 31 through a pipe line 42. In order to provide for the use of a single one of the oil burners 35 or 36, these pipe lines 4| and 42 are shown as terminating in two separate conduits that are adapted, by means of valves 43 and 44 to limit the flow of fuel oil and air to one or the other of the burners 35 and 36. Immediately below the oil burners 35 and 36, the combustion chamber or firebox II is provided with hinged covers 45 and 46 through which access may be had to the burners, and which also function as dampers to control the draft through the firebox H. .At the upper rear end of the combustion chamber ll there is a supporting shroud 41 upon which a stack 48 is pivotally mounted by a hinge 49. As shown, the hinge 49 is so arranged that the stack 48 may be lowered into a horizontal position to provide clearance in transporting the/ apparatus from one location to another. At the forward end of the combustion chamber H there is a supporting bracket 50 upon which the end of the stack 43 rests when in its lowered position. T protect the interior of the combustion chamber H from foreign matter when the stack 48 is down, and to also regulate the draft therethrough, the shroud 41 is provided with a damper 5| that is adapted to completely close this opening and al regulate the draft through the stack 46 when the apparatus is in use. Figures 2 and 3 of the drawings also show the outer wall of the combustion chamber or firebox II as provided with a series of saddle-like hooks or brackets 52 that are adapted to carry additional lengths of pipe or flexible hose 53 through which connections may be established between the intake of the pump l3 and a source of supply, and from the branch conduits ill or 19 of the discharge conduit IE to a point of discharge.

Before taking up a description of the operation of the invention in connection with Figure 5 of the drawings, reference is made to Figures 6. 'I and 8 of the drawings for a detailed description of a particular form of retort that has been found to operate very satisfactorily in the heating of asphalt, oil or other viscous material, .as contemplated by this invention. As shown in Figure 6, the central conduit 23 of the retort 12 extends through two spaced headers 54 and 66 between which there is arranged a plurality of spaced axially extending tubes or flues 56 through which the asphalt, oil or other v scous material entering at the inlet conduit [4 is circulated back and forth from one header to the other until it is discharged through the discharge pipe [5. As the asphalt, oil or other viscous material enters the inlet conduit l4, it will flow through the central conduit 23, as indicated by arrows, until it strike a blocking partition 51 formed in ,the central conduit 23. At the nearest side of th s blocking partition 51, the conduit 23 is provided with a discharge port 53 that causes the asphalt, oil or other viscous material to flow outwardly and into a series of the inner adjacenttubes 59 where it will flow in a reverse direction and into the header 54. At this point the asphalt, oil or other viscous material will be redirected through make one additional pass through-the retort until it as are illustrated in Figures 7 and 8, of the drawings, divide the headers 54 and 55 insuch a manner that several tubes 56 areconnected in groups of three tubes per pass. As the asphalt, oil or other viscous material is discharged from the central conduit 23 throughthe port 58, as shown return toward the observer in the next three tubes arranged counter-clockwise therefrom and then back to the header 50 through the next three tubes 56 and toward the observer through the bottom three of the tubes 56 shown in this figure. At this point .the asphalt; oil or other viscous material flow will be directed by th adjacent radial bailles through three of the next outer concentric row of tubes where its flow will continue as above and be repeated with respect to each concentric row until it flowstoward the observer through the three isolated tubes 55 at the top of thisilgure. At this jointthe asphalt, oil or other viscous material will flow inwardly through the manifold 60 to the central conduit 23 at the other side of the blocking partition 51 and out through the discharge pipe 15. Upon referring to Figure 8, it will be noted that the header G is divided into radial and concentrically arranged chambers, each of which have six tubes, so that the asphalt, oil or other viscous material will enter each chamber through three of the tubes and return to a corresponding chamber in the header 55 through the other three tubes. This arrangement distinguishes from that provided in the header 55 in that in the latter header the partitions are so arranged as to carry the flow of the asphalt, oil or other viscous material from one concentric arrangement of tubes or flues 56 to an outer concentric arrangement of the tubes. When the tubes are connected in this manner by the radial and concentric partitions, as illustrated in these figures of the drawings, it will be seen that the asphalt, oil or other viscous material will flow twice in each direction in the inner concentric arrangement of tubes immediately adjacent the central conduit 23. In the next concentric circle of tubes, the asphalt, oil or other viscous material will pass three times in each direction and as each concentric arrangement of tube is reached, the asphalt, oil or other viscous material will is discharged thereirom.

It has been found that with this particular type of retort, an increase in the temperature of 10,000 gallons of road oil can be obtained at the rate of approximately 60 F. per hour. This means that starting with a carof oil at 200 F., it is possible to start unloading the tank car with the discharged oil at a temperature of 450 F. in approximately two hours. A will hereinafter appear, this is accomplished by first circulating the oil through the retort at a. fairly high rate of speed until the temperature of the oil entering the retort i2 is increased to approximately 315 F. With the oil at this temperature, it is then possible, by changing its rate of flow to a slower speed, to thus raise the temperature of the oil an additional 135 F. in one pass through the retort l2 and deliver it to the distributing truck at a temperature of 450 F. The oil at this latter temperature may be pumped through the retort at a rate of 75 gallons per minute. It will be understood that the rate of flow through the retort I! may be adjusted to any desired rate. For example, as th temperature of the oil in in each direction in Figure 'I, it will flow away from'the observer through the three communicating tubes 56 and the tank car is increased, the pumping speed may also be increased until finally the oil can be pumped at a rate of 260 gallons per minute with a temperature rise' of approximately 40 F. per pass through the retort. When operating at this latter rate, the retort will be capable of increasing the temperature of 1000 gallons of the flow ing oil 40 F. in about 4 minutes. A further advantage possessed by this retort is that during the heating operation the oil is in continuous circulation and, as a result, it will be uniformly heated throughout and will not be exposed to any overheating due to an accumulation of the oil in a hot zone of the retort, as would be the case with a simple drum or tank type of retort.

- Reference is now made to Figure 5 of the drawlugs for a description of the operation of my improved heating and transferring apparatus. As here illustrated, the apparatus described above'is located between a railway tank car 6i and a highway tank truck 62, this being a typical setup, such as is possible where the tank car 6! has been shuntedv to a suitable siding for transfer of the contents of the tank car 6! to a distributing vehicle. As here illustrated, the intake of the pump i3 is connected to the bottom of th tank car 61 by means of one of the flexible conduits 53, and the branch conduit I8 of the discharge pipe i5 is shown as leading to the top of the tank truck 52 for the purpose of loading the same with the asphalt, oil or other viscous material after its temperature has been raised to the desired degree. Atthis point it will be noted that the tank truck 62 is shown as having a sprinkler head 63 by means of which the heated asphalt, oil or other viscous material may be distributed upon the surface of the highway in accordance with the usual practice. It will be understood, however, that this tank truck 62 may be of any suitable type. The branch conduit IQ of the discharge pipe I5 is also here illustrated as havin an extending connection which leads to the top of the tank car 61 When the apparatus has been positioned andconnected up in this manner, it will be seen that the flow of the asphalt, oil or other viscous material may be controlled by the three-way valve it so that it can be recirculated through the retort l2 until its temperature has been raised to the desired degree, and finally, it can be directed into the tank truck 52 for application to a highway surface. As here illustrated, the pump [3 is driven by the internal combustion engine 20 through the conventional transmission gear which is controlled by the gear shift lever 22. This figure of the drawings aisoshows the internal combustion engine 20 as having a drive pulley. 64 at its forward end over which a V-belt 65 that forms a driving connection with a pulley 66 upon the shaft of the air compressor 34 passes. Cooperating with the V-belt 65 and operating as a belt tightening idler, there is an additional pulley 5? that is carried by the driving shaft 33 previously described as operating through the sprocket chain 30, the reduction gearing 3| and the sprocket chain 32 to rotate the retort 12. At this point it should also be noted that the discharge conduit ll of the pump 13 is provided with a pressure gauge 68 eter 68. The discharge pipe iii of the retort I2 is also shown as having an indicating thermometer 70 mounted thereupon. If it is now assumed that the apparatus is connected up as above, it will be seen that the pump 53 will operate to pump the asphalt, oil or other viscous material from the tank car 6! through the retort i2 and back to and an indicating thermomthe top of the tank car 6| or to the tank type vehicle 62, as will be determined by the position of the three-way valve 16. As the internal combustion engine 20 operates through the above described driving connection to rotate the retort l2, its speed may be regulated in the conventional manner by throttle and spark control to provide, within certain limits, any desired relative speed of rotation for the retort l2. At the same time. it will be possible, without changing the speed of the internal combustion engine 20, to operate the pump l3 at any one of the three, or possibly 4, different speeds, depending upon the nature of the transmission gearing controlled by the gear shift lever 22 and, as a result, the flow of asphalt, oil or other viscous material and the rotation of the retort I2 may be regulated to values which are best suited to its prevailing temperature and viscosity.

When the apparatus is initially put in operation, as when new, the pump, the circulation providing conduits, the retort headers 54 and 55, and the tubes or fiues 58 will be clean and will afford a free circulatory path for the asphalt, oil or other viscous material. after any prolonged shutdown, there may be an accumulation of the more viscous materials in the low points of the circulation system. In some cases this accumulation of viscous material, when cooled. may restrict the path for the flow of asphalt, oil or other viscous material at these points and, therefore, upon initially starting the apparatus after any such a shutdown, it will be found desirable to first subject the retort l2 to a preliminary heating while in-slow rotation and 3 prior to a starting of the pump I3. This will serve to liquify any accumulated viscous material so that when the pump is started, there will .be no serious obstruction to the free flow of the asphalt, oil or other viscous material. Under normal circumstances, such a procedure will be all that is necessary in starting the apparatus. However. in order to safeguard against the possibility of a bursting stress being established within the circulatory system, and particularly in the headers 54 and 55 and the fines 56, I may provide a relief or by-pass valve H, such as is shown in Figures However, it will be found that 1 and 2 of the drawings, as mounted immediately I above the pump l3. This relief or by-pass valve II has a threaded shaft 12 by which it may be adjusted to render it operative upon the existence of any predetermined back-pressure in the conduit H. In this manner the pressure exerted by the pump l3 upon the asphalt, oil or other viscous material in the pipe l4 may be controlled and limited to a safe value. When the by-pass valve II operates, as would be the case in the event of a too restricted or a complete stoppage within the circulation system or retort I2, the asphalt, oil or other viscous material will flow from the pump out through a discharge conduit 13 to any suitable point of discharge, preferably back to the tank car. With this arrangement it will be seen that the operation of the pump 13 may be continued and while the oil may flow out through the discharge conduit 13, the pump will at the same time maintain a predetermined safe pressure upon the asphalt, oil or othepviscous material in the pipe l4, and after the apparatus has operated for a short period under these conditions, any restriction that may exist will be automatically removed and then'the by-pass valve II will close and assume its normal condition of operation and the asphalt, oil or other viscous material circulated by the pump I! will then flow through the apparatus as above described.

While I have shown the entire assembly as mounted upon two axles equipped with wheels, tires and brakes, it will be understood that the' unit may be mounted upon a single axle with a 5th wheel assembly that may be attached over the rear axle of a separate truck to thus form a semi-trailer unit. The apparatus may also be mounted upon a self-propelled vehicle, or constructed as a stationary unit by mounting the supporting frame on a permanent foundation.

It will also be understood that while I have described and illustrated specific devices and arrangements, the invention is not necessarily limited to the specific means disclosed, but may be embodied in other ways that will suggest themselves to persons skilled in the art. It is believed that this invention is new and all such changes as come within the scope of the appended claims are to be considered as part of this invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. An apparatus for preheating and transferring asphalt, heavy road oil, or other viscous material from a source of supply to a transports ing tank trunk, comprising the combination of a source of supply container, a conduit connected to said container, a rotatable material heating retort, a second conduit connected to said retort, pump means through which said first and second conduits are connected for maintaining a flow of the material from said source of supply container to said retort, an outlet conduit leading from said retort for returning the heated material to said source of supply container, a prime mover having a driving connection for rotating said material heating retort, a second driving connection between said prime mover and said pump, whereby said pump will operate to maintain a circulation of the material through said retort as said retort is rotated by said primemover, a discharge conduit connecting with the outlet conduit of said retort for directing the heated material to the transporting tank truck when its temperature and viscosity reach the desired values, and means whereby the operating speed of said pump may be changed relative to the speed of rotation of said retort.

2. An apparatus for transferring asphalt, heavy road oil, or other viscous material from a source of supply to a transporting tank truck, comprising the combination of a source of supply container, a rotatable circulation type heating retort, a conduit forming a connection between said container and said retort, pump means in said conduit for maintaining a flow of the material of supply container for recirculation through said retort, a prime mover for rotating said heating retort at a constant speed, a changeable speed driving connection between said prime mover and said pump, whereby the circulation of the material through said retort may be changed while said retort is rotated at said constant speed, a discharge conduit connecting with the outlet conduit of said retort, and valve means for directing said recirculating material from said retort to the transporting tank truck.

3. In an apparatus for preheating asphalt, heavy oils and like viscous material prior to its transfer from a railway tank car to a transporting vehicle for application to a highway, the com retort.

bination of a tank 'car, a wheeled vehicle having a supporting frame adapted to be positioned adjacent said tank car, an oil fired combustion chamber supported upon said frame, a rotatable retort having inlet and outlet ports mounted within said combustion chamber and through which a circulation of the material is maintained, a pump mounted upon said frame adjacent said combustion chamber, a conduit for connecting said pump to said tank car, a second conduit for connecting the discharge of said pump to the inlet port of said retort, a connection between the outlet port of said retort and said railway tank car and forming with said first and second conduits a closed recirculating system, a prime mover unit mounted upon said frame, a driving connection between said prime mover and said pump, a direct driving connection between said prime mover unit and said rotatable retort,

whereby said retort will be rotated at a substantially constant speed by said prime mover, and a changeable speed transmission in the driving connection'between-said prime mover and said pump for changing the operating speed of said pump without changing the speed of said prime mover, whereby the rate of circulation of mate- '7 bination of a railway tank car, a. wheeled vehicle having a supporting frame adapted to be positioned adjacent said tank car, an oil fired com- I bustion chamber supported upon said frame, a

rotatable retort mounted within said combustion chamber and having inlet and outlet ports for a circulation of material therethrough, -.a pump mounted upon said frame, a conduit leading from the discharge outlet of said pump to the inlet port of said retort, a second conduit leading from said tank car to said pump, a third conduit extending from the outlet port of said retort adapted to complete a closed recirculating system through said tank car said pump and said retort, a prime mover unit mounted upon said supporting frame, a driving connection between said prime mover and said pump, a fixed driving connection between said prime mover unit and said retort, whereby said retort will be rotated at a speed corresponding to the speed of said prime mover, and a changeable speed transmission in the driving connection between said prime mover and said pump for changing the operating speed of said pump without changing the speed of said prime mover, whereby the rate of circulation of the material through said retort may be changed without changing the speed of rotation of said 5. In an apparatus for transferring asphalt, heavy road oil and other viscous material from a source of supply to a transporting truck, the combination of a rotatable circulation type heating retort, pump means for circulating the material to be heated through said retort, a prime mover for rotating said heating retort at a constant speed, and a changeable speed driving connection between said prime mover and said pump, whereby the circulation of the material through said retort may be increased or decreased without changing the speed of rotation of said retort.

6. In an apparatus for heating asphalt, heavy oils and like viscous material prior to its transfer from a railway tank car to a transporting vehicle for application to a highway, the combination of a supporting frame adapted to be positioned adjacent a railway tank car, an oil fired combustion chamber supported upon said frame, a rotatabl retort mounted within said combustion chamber and through which the material may flow, a pump mounted upon said frame adjacent said combustion chamber for maintaining a circulation of material through said retort, a prime mover unit mounted-upon said frame, a direct driving connection between said prime mover unit and said rotatable retort, whereby said retort will be rotated. at a substantially constant speed by said prime mover, a second driving connection between said prime mover and said pump, and a changeable speed transmission in said second driving connection by which the operating speed of said pump may be changed without changing the rotational speed of said retort.

7. In a mobile apparatus for heating and transferring asphalt, heavy oil or other viscous material from one point to another, the combination of a wheeled vehicle having a supporting frame, a combustion chamber supported centrally upon said supporting frame, a circulating flue-type retort rotatably mounted within saidcombustion chamber, an internal combustion engine mounted forwardly of said combustion chamber, a direct driving connection between said internal com-' bustion engine and said retort for rotating said retort at a speed determined by the speed of said internal combustion engine, a pump mounted upon said supporting frame adapted to maintain a circulation of material through said retort, a second driving connection between said internal combustion engine and said pump, and a speed reducing gear in said latter driving connection, whereby the operating speed of said pump may be changed without changing the speed of said internal combustion engine and said retort.

8. In an apparatus for heating and transferring asphalt, heavy road oil or other viscous material from a source of supply to a transporting tank truck, the combination of a rotatable heating retort, pump means including suitable connecting conduits for maintaining a flow of the materia1 from a source of supply to said retort, a prime mover having a-driving connection for rotating said heating retort, a second driving connection between said prime mover and said pump, whereby said pump will operate to maintain a circulation of material through said retort as it is rotated by said prime mover, and means whereby the rotative speed of said retort and the operating speed of said pump may be changed relative to each otherwithout changing the operating speed of said prime mover.

CARL F. GERLINGER. 

